Flow through impellers and fluid machines employing same

ABSTRACT

A hydraulic pump has a rotary impeller which contains a multiplicity of slots, each in the form of an equilateral triangle with its longitudinal axis each at a certain angle to a radial line thereto from the axis of the impeller shaft. The slots cause the impeller to act as an inclined plane to increase the flow.

United States Patent [1 1 Treese,

[451 Nov. 12, 1974 1' FLOW THROUGH IMPELLERS AND FLUID MACHINESEMPLOYING SAME [76] Inventor: David W. Treese, 207 l-lolmer Rd.,

Greece, N.Y. 14626 [22] Filed: Feb. 20, 1973 [21] Appl. N0.: 333,815

[52] US. Cl. 415/213, 416/178 [51] Int. Cl. F04d 3/00 [58] Field ofSearch 415/213, 72, 76, 215, 73,

I [56] References Cited UNITED STATES PATENTS 655,830 8/1951 GreatBritain 416/183 507,631 9/1930 Germany 416/183 516,089 l/l931 Germany548,474 4/1932 Germany 435,591 12/1947 Italy .1

France 416/182 Primary ExaminerI-Ienry F. Raduazo Attorney, Agent, orFirmManin Lukacher 57 ABSTRACT A hydraulic pump has a rotary impellerwhich contains a multiplicity of slots, each in the form of anequilateral triangle with its longitudinal axis each at a certain angleto a radial line thereto from the axis of the impeller shaft. The slotscause the impeller to act as an inclined plane to increase the flow.

12 Claims, 6 Drawing Figures 998,889 7/1911 Fraser 416/181 1,046,09212/1912 Marburg, .lr. 415/74 2,808,225 10/1957 Johnson 415/73 3,709,6351/1973 lvey 416/183 FOREIGN PATENTS OR APPLICATIONS 256,542 0/1927 GreatBritain 1. 416/183 PATENTEUnuv 12 I974 SHEET 1 OF 2 F/GZ The presentinvention relates to fluid (both liquid and gas) impellers andparticularly to impellers for hydraulic pumps and motors.

The invention is especially suitable for use in a pump for fluid drives,as in automotive applications wherein the fluid is oil which is pumpedat low pressures suitable for driving a prime mover which may be aturbine or an impeller also embodying the invention, the power and/orspeed of the drive being controllable at the pump as by changing thespeed of rotation of the pump impeller. Other applications for theinvention in propellers for boats, sump pumps in internal combustionengines, and in various types of fluid pumps and motors are alsoavailable.

Various types of impeller configurations have been employed in hydraulicand other fluid machine's. Some use fins or blades while other useaugers. Limitations, however, exist upon the amount of flow which can behandled and the pressures which may be achieved by virtue of the shapeand size of the impeller. In addition, the control characteristics ofthe impeller (viz., impeller speed versus flow or pressure obtained) isrelatively insensitive to changes in impeller speed, thus requiringadditional devices, such as valving, to effectuate such control. Anotherdisadvantage of existing types of impellers is the need for large sizesof impellers to provide large flow capacity; thus, where largequantities of fluid must be moved, huge pumps incorporating such largeimpellers have been required.

Accordingly, it is an object of the present invention to provideimproved fluid impellers.

It is a further object of the present invention to provide improvedimpellers suitable for use in hydraulic pumps and motors.

It is a still further object of the present invention to provideimproved impellers which obtain large fluid flow without requiring largevolume or space.

It is a still further object of the present invention to provide animproved impeller which is effectively free from clogging by foreignparticles.

It is a still further object of the present invention to provide animproved impeller which can be manufactured without adhering to closedimensional tolerances.

It is a still further object of the present invention to provide animproved impeller which is adaptable to manufacture by varioustechniques, such as die casting, machining, or sheet metal fabrication.

It is a still further object of .the present invention to provide animproved fluid pump.

It is a still further object of the present invention to provide animproved fluid pump wherein flow and/or pressure is readily controlledby varying impeller speed.

Briefly described, an impeller provided in accordance with the inventionincludes a generally cylindrical body which is mounted on a shaft and isrotatable therewith. The body of the impeller has a plurality of slots.Each slot is its own pressure producer. The slots are desirablytriangular in shape, and preferably equilaterally sided so that thepressure on the sides of the triangles are in cancelling relationship;thus permitting the walls of the slots to be thin. Each of the slotsbeing spaced from the axis of the shaft and extending longituchamber 38is defined between the outlet face 34 and dinally between the oppositeends of the body. Each of the slots has a longitudinal axis which iscanted so that the projection of the axis upon the shaft axis in thedirection of fluid flowdefines an acute angle. The slots act as inclinedplanes causing an increase in flow as the cylindrical body rotates. Alarge number of slots may be disposed in rings, with the triangularcross sections thereof in nested relationship so as to provide a largeflow capacity in an extremely small volume. The triangular slotsdiminish in size in accordance with their radial distance from the axis.The pressure cancellation feature of the slots configuration facilitatesthin walls which permit close nesting.

The foregoing and other objects and advantages of the present inventionas well as additional features thereof will become more readily apparentfrom a reading of the following description in connection with theaccompanying drawings in which:

FIG. 1 is a perspective view of a fluid machine (a hydraulic pump)embodying the invention;

FIG. 2 is a sectional view of the pump shown in FIG.

FIG. 3 is a perspective view showing a section through the impeller ofthe pump shown in FIG. 1, the section being taken generally along theline 33 in FIG. 2;

FIG. 4 is a front view showing the inlet face of the impeller;

FIG. 5 is a front view showing the outlet face of the impeller; and

FIG. 6 is a schematic view illustrating the dimensional and positionalrelationships of a typical slot in the impeller with respect to therotational axis of the impeller.

Referring to FIG. 1 there is shown a housing 10 consisting of acylindrical section 12 sandwiched between a pair of end plates 14 and16. An inlet pipe 18 which may be coupled to a hose (not shown) extendsfrom the end plate 14. An outlet pipe 20 which also may be coupled to ahose, extends from the other end plate 16. As shown in FIG. 2, the endplates and the center section are assembled in pressure-tightrelationship by bolts 22 which compress O-ring seals 24. A shaft 26 isjournalled in the end plates 14 and 16 by bearings 26 and 28. Animpeller 30 is rotatably mounted on the shaft as by being welded orkeyed thereto. The impeller 30 is a cylindrical body having end faceswhich are the inlet face 32 and outlet face 34 of the cylindrical bodyof the impeller; The impeller may be fabricated from sheet metal insections, such as the section shown in FIG. 3, which sections areassembled together as by soldering or welding.

An inlet chamber 36 is defined between the inlet face 32 and theinterior wall of the end plate 14. An outlet the inner wall of the endplates 16. The pipes 18 and 20 respectively define an inlet port 40 andan outlet port 42 of the pump.

The impeller has a plurality of slots 44 which extend longitudinallythrough the impeller body from the inlet face 32 to the outlet face 34.The slots are arranged in concentric rings. Each slot is a triangleapproximately equilateral in cross section, but of progressively smalleraltitude in accordance with its radial distance from the axis 46 of thecylindrical impeller body; the axis 46 also being the axis of the shaft26.

Consider a section of slots as shown in FIG. 3. There are two layers ofadjacent slots 48 and 50 which are in nested relationship. This nestedrelationship provides a large number of slots in a relatively smallvolume constituted by the body of the impeller, thus affording largeflow capacity in a relatively small volume or space. The slots may beconstructed out of sheet metal. For example, upper and lower sheets 52and 54 sandwich a corrugated member 56. The corrugated member and thesheets define a section of nested triangular slots. The nestedrelationship of the slots defines consecutive sectors (viz., pre-shapedsections which taper inwardly toward the axis 46). The slots may also beformed by machining or milling them out of a solid piece of metal or bycasting. It will be appreciated that the thickness of the wall betweenadjacent triangular slots determines the number of slots which can beaccommodated in a given impeller volume.

An important feature of the invention is the orientation of the slotswith respect to the rotational axis of the impeller (viz., the axis 46).As shown in FIG. 6, each slot, such as the typical slot 60 has alongitudinal axis 62. The longitudinal axis is disposed so that itsprojection on the axis 46 forms an acute angle. In the illustratedembodiment of the invention this angle is 45. Other suitable angles are30, 60 and 75. It will be noted that this angle is formed between aradial line extending from the axis 46 to the longitudinal axis 62. Itwill be observed that the 45 angle is formed between the intersection ofthe longitudinal axis 62 and the plane projected on to the axis 46 inthe direction of fluid flow. This orientation of the slots causes theslots to be skewed or canted at different angles with respect to theinlet face 32 and the outlet face 34 as shown in FIGS. 4 and 5. It isalso desirable that the slots be canted in a direction toward the axis46. This provides for a downward orientation of the slots toward theaxis 46 in a direction from the inlet face 32 towards the outlet face34.

As shown in FIG. 6 the slots may be tapered also in the direction of theinlet face 32 towards the outlet face 34. The angle of this taper ispreferably l /z as shown in FIG. 6 and may be provided by having one ofthe adjacent walls of each slot perpendicular or at angles of 90 to eachother, while the other wall is at an angle of 885 to its adjacent wall.

In operation the slots in the impeller act as inclined planes forcinglarge volumes of fluid in the flow direction from the inlet to outletfaces of the impeller 30. The large number of slots or fluid cams whichare provided in the impeller provide a very sensitive impeller speedversus flow control characteristics. Thus, control of flow and pressureis accomplished by varying the speed of rotation of the shaft 26.

It is desirable to adjust the size of the chambers 36 and 38 inaccordance with the flow capacity desired. For higher flows and lowerpressures the chambers may be larger whereas for higher pressures andlower flows the chambers may be of the smaller volume. Large inlet andoutlet ports 40 and 42 may readily be accommodated since flowlimitations are reduced by virtue of the design of the impeller 30.

From the foregoing description it will be apparent that there has beenprovided an improved fluid machine. An embodiment of the machine in theform of a hydraulic pump has been illustrated to explain the invention.Variations and modifications in the herein described pump willundoubtedly suggest themselves to those skilled in the art. For example,each of the sections of slots is canted with respect to the inlet andout let faces 32 and 34 of the impeller body, inasmuch as these sectionsare formed from sheet metal. While such canting provides improvements inaffording additional cam action at the faces, it may be desirable shouldcasting or other manufacturing processes be used for the end faces to beplanar surfaces. Other variations and modifications in the hereindescribed embodiment of the invention will undoubtedly suggestthemselves to those skilled in the art. Accordingly, the foregoingdescription should be taken merely as illustrative and not in anylimiting sense.

What is claimed is:

1. A rotary impeller through which fluid flows, which comprises:

a shaft having an axis,

a generally cylindrical body mounted on said shaft and rotatabletherewith,

a plurality of triangular slots in said body, each of said slots beingspaced from said axis and extending in a substantially straight linebetween the opposite ends of said body,

each of said slots having a longitudinal axis and each of said slotsbeing disposed with the projection of its longitudinal axis upon saidshaft axis in the direction of said fluid flow defining an acute angle.

2. The invention as set forth in claim 1 wherein each of said slots isalso disposed with its longitudinal axis tclanted toward said shaft inthe direction of said fluid 3. The invention as set forth in claim 1wherein each of said slot longitudinal axis intersects a radial linefrom said shaft axis at said acute angle.

4. The invention as set forth in claim 3 wherein said acute angle isfrom 15 to 5. The invention as set forth in claim 4 wherein said slotshave at least one wall thereof which tapers inwardly in the direction ofsaid fluid flow.

6. The invention as set forth in claim 5 wherein said taper is at anangle of about 15.

7. The invention as set forth in claim 1 wherein said triangles areapproximately equilateral.

8. The invention as set forth in claim 4 wherein said slots are arrangedin a plurality of rings disposed circumferentially around said shaftaxis at progressively greater radial distances therefrom, each ringcontaining a plurality of said slots, said rings of slots in turnoccupying sectors of said cylindrical body.

9. The invention as set forth in claim 8 wherein each ring contains aplurality of triangular slots in nested relationship with the slots ofthe rings adjacent thereto.

10. The invention as set forth in claim 8 wherein the slots in each ringare triangular and have progressively greater altitudes with greaterdistances from said shaft axis.

11. The invention as set forth in claim 1 including a housing, saidimpeller beingdisposed in said housing with said shaft journalled forrotation therein, said housing and the end of said body facing towardsaid fluid flow and one wall of said housing defining an inlet chamber,and wall of said housing opposite to said one wall and the end of saidbody facing away from said fluid flow defining an outlet chamber, andinlet and outlet ports for said fluid respectively communicating withsaid inlet and outlet chambers.

12. The invention as set forth in claim 11 including means for drivingsaid shaft in a clockwise direction to pump said fluid from said inletto said outlet ports in said flow direction.

1. A rotary impeller through which fluid flows, which comprises: a shaFthaving an axis, a generally cylindrical body mounted on said shaft androtatable therewith, a plurality of triangular slots in said body, eachof said slots being spaced from said axis and extending in asubstantially straight line between the opposite ends of said body, eachof said slots having a longitudinal axis and each of said slots beingdisposed with the projection of its longitudinal axis upon said shaftaxis in the direction of said fluid flow defining an acute angle.
 2. Theinvention as set forth in claim 1 wherein each of said slots is alsodisposed with its longitudinal axis canted toward said shaft in thedirection of said fluid flow.
 3. The invention as set forth in claim 1wherein each of said slot longitudinal axis intersects a radial linefrom said shaft axis at said acute angle.
 4. The invention as set forthin claim 3 wherein said acute angle is from 15* to 75*.
 5. The inventionas set forth in claim 4 wherein said slots have at least one wallthereof which tapers inwardly in the direction of said fluid flow. 6.The invention as set forth in claim 5 wherein said taper is at an angleof about 1.5*.
 7. The invention as set forth in claim 1 wherein saidtriangles are approximately equilateral.
 8. The invention as set forthin claim 4 wherein said slots are arranged in a plurality of ringsdisposed circumferentially around said shaft axis at progressivelygreater radial distances therefrom, each ring containing a plurality ofsaid slots, said rings of slots in turn occupying sectors of saidcylindrical body.
 9. The invention as set forth in claim 8 wherein eachring contains a plurality of triangular slots in nested relationshipwith the slots of the rings adjacent thereto.
 10. The invention as setforth in claim 8 wherein the slots in each ring are triangular and haveprogressively greater altitudes with greater distances from said shaftaxis.
 11. The invention as set forth in claim 1 including a housing,said impeller being disposed in said housing with said shaft journalledfor rotation therein, said housing and the end of said body facingtoward said fluid flow and one wall of said housing defining an inletchamber, and wall of said housing opposite to said one wall and the endof said body facing away from said fluid flow defining an outletchamber, and inlet and outlet ports for said fluid respectivelycommunicating with said inlet and outlet chambers.
 12. The invention asset forth in claim 11 including means for driving said shaft in aclockwise direction to pump said fluid from said inlet to said outletports in said flow direction.